A Christian's response to ethical emotivism would be?

Of course, there would be nothing to say that a Christian couldn't be an ethical emotivist. But because ethical emotivists view value statements (e.g. "stealing is wrong") as essentially emotional statements (e.g. "I don't like stealing") rather than statements of truth, Christian ethicists tend to regard ethical emotivism as morally relativist to the point of absurdity. Arthur F. Holmes's observation in his book Ethics: Approaching Moral Decisions, is typical of this critique:

When we argue about moral issues, however, to what do our arguments appeal? We must be debating something...Right and wrong are not...just emotivisms. They are evaluative, interpretive forms which refer to nonempirical concepts of rightness or wrongness...

They refer, Holmes argues, to "something external to us, something both extra-mental and extra-linguistic." There exist in the world, Christian ethicists argue, moral positions which can be understood. For most Christians, these moral positions could be rooted in Scriptural authority, or they could be in a sort of natural law.